Structural and dielectric properties of epitaxial SrTiO3 films grown on Si(100) substrate with TiN buffer layer

Abstract

SrTiO 3 thin films have been grown on Si(100) substrates by pulsed laser deposition using an epitaxial TiN film as a buffer layer, and their structural and dielectric properties were investigated as functions of deposition parameters. X-ray diffraction analysis showed that the SrTiO3 films were grown epitaxially in the wide range of substrate temperatures (400–650 °C) and ambient oxygen pressure (10−5 Torr–150 mTorr) with an orientation relationship of SrTiO3(100) // TiN(100) // Si(100) and SrTiO3〈010〉 // TiN〈010〉 // Si〈010〉. The crystallinity of the epitaxial films was improved with the increase of the substrate temperature and decrease of the ambient oxygen pressure, while the film surface morphology was degraded with increasing either of the two parameters. The relative dielectric constant of the films was revealed to depend both on the crystallinity and on the surface roughness of the films, the highest value of which was εr=270 at 1 MHz, comparable to that of bulk SrTiO3.